Issues with the rotating tool

[LostCoastlines]

Hi there

So I am having some issues with the rotating tool. I am creating a map, and I want to rotate a layer around 10 degrees to fit in with the rest of the image. The only issue is that it rearranges and adds the pixels around on the layer image. 

I was wondering if there was a way to prevent this or a work around to it? I've tried to deal with it and edit the pixels manually, but the image seems to too distorted and rearranged for it to work.

For reference here part of the image


And here is the image rotated


Any help/advice would be much appreciated! Even if you know a program I can export the map to, rotate then export back to GIMP

Thank you

[Blighty]

I'm afraid that from your description I am not understanding what the problem is. The two images show that the image has been rotated as expected.

Some thoughts:

1) Editing a bitmap does create some distortion. Pixels are created and destroyed in the rotate process. If you rotate 10 degrees and it is not enough don't rotate a further small amount. Use Undo and start again, this time rotating say 10.5 degrees.

2) You may need to use Image > Fit canvas to layers after rotating.

[rich2005]

The problem is the image has no anti-aliasing. Rotating 10° is moving pixels to new positions in a rectangular grid. Never going to be exactly the same order.

With a straight rotate without anti-aliasing set interpolation to none.



No real easy solution, trying a few things & jumping through hoops -
Selection -> selection to path -> rotate path -> path to selection -> fill selection -> threshold to remove antialiasing. Gives a slightly better result, but is it worth the effort.

Edit:
A bit more dabbling, you might get it a little better, if you slightly blur the image first.
Then rotate with regular interpolation cubic or no-halo
Then remove the anti-aliasing with threshold.